Halogenated organosilicon compounds



Patented Aug. 7, 1945 HALOGENATED ORGAN OSIIJCON COMPOUNDS Winton I. Patnode, Schenectady, N. Y., and Robert W. Schiessler, State College, Pa., assignors to General Electric Company, a corporation or v New York No Drawing. Application March 4, 1942. Serial No. 433,328

scram ('01. 260-4507) The present invention relates to novel halogenated organosilicon compoundsand to a process for preparing such compounds. It is particularly concerned with halogenated organosilicon compounds having the formula XiSHCHr) nSiXaY wherein X represents a halogen atom, Y represents a hydrogen atom or a halogen atom of the same type as that represented by X, and n is an integer equal to or greater than 1.

Organosilicon compounds of the type represented by the formula R481, wherein R is a saturated phenyl, etc. radical, have beenknown for many years. Organosilicon compounds of the type represented by the formula RaSi(X)4-, wherein R is a saturated hydrocarbon radical, X is a halogen atom and a is an integer from 1 to 3 are also known. Similarly, compounds of the latter type in which one or more of the hydrocarbon radicals are replaced by hydrogen are known.

In addition to these simple organosilicon compounds which contain but one atom of silicon, more complex compounds containing more than one atom of silicon are also known. However, in these known compounds, the atoms of silicon are either linked directly to each other, as for example in hexachlorodisilane ClsSi-SiCls, or are linked by oxygen, as for example in the compounds obtained by hydrolysis of chlorosilanes. Compounds of the latter type are described for example in Patent 2,258,218 issued to Eugene G. Rochow.

such as methylene chloride, ethylene chloride. etc., and silicon at elevated temperatures in the presence of a metallic catalyst, particularly a copper catalyst.

are more fully described in connection with the hydrocarbon radical such as a methyl,

The present invention relates to a new class of halogenated organosilicon compounds in which the atoms of silicon are linked to each other by carbon atoms; Examples of such compounds Trichlorosiiyldichlorosilylmethane,

ClaSiCHzSiClzH Bis(trichlorosilyl) methane, ClaSiCHaSiCh ,2-bis(trichlorosilyl) ethane, C13SiCH2CH2SiC13 Trichlorosilyldichlorosilylbutane,

I ClaSi (CH2) 4SiCl2H Compounds of the above type are prepared in accordance with our invention by effecting reacpreparation of organosilicon halides containing one silicon atom per molecule in the copending application of Eugene G. Rochow, Serial No. 412,459, 'iiled September 26, 1941, and assigned to the same assignee as the present invention. Preferably the silicon and copper are employed in the form of solid, porous contact masses consisting of a molded mixture of silicon and copper which has been flred under reducing conditions. Such contact masses and their preparation are more fully described and claimed in the copending application of Winton I. Patnode, Serial No. 412,461, filed September 26, 1941, and assigned to the same assignee as the present invention.

In order that those skilled in the art better may understand how the present invention may be carried into eifect, the following illustrative examples thereof are given:

Example I A stream of dry, oxygen-free nitrogen was passed through a reservoir of methylene chloride, CHzClz, at a rate oi. 300 c. e. per minute. The efliuent mixture of nitrogen and methylene chloride vapors was passed into a heated tube filled with pellets of a silicon-copper contact mass r containing a mixture of 9 parts silicon and 1 part copper which had been fired in hydrogen at 1050 C. for about two hours. By holding the temperature of the methylene chloride reservoir between 25 and 27 0., the methylene chloride vapor was carried into the reaction tube at the rate of about 0.8 gram per minute. The use 0! anitrogen atmosphere as described herein is not part of our invention but is rather the subject matter of the copending application of M. M. Sprung and W. F. Gilliam, Serial No. 433,293, filed concurrently herewith and assigned to the same assignee as the present invention.

The reaction tube used in this and subsequent examples was about 24 inches long and 1% inches indiameter. With the temperature of the tube and its contents held at about 300 C., approximately per cent of the methylene chloride either reacted with the silicon to form a number of organosilicon compounds or condensed alon tion between a symmetrical hydrocarbon dihallde with-these compounds when the gaseous products passing from the exit end of the tube were condensed and collected in traps cooled by a mix-, ture of ice and water.

That portion Of themethylene chloride which could 'not be accounted for was either swept through the condensing traps by the nitrogen flow-or reacted with the silicon to form low, boiling materials such as 1101, SlHrCla, etc., which were not completely recovered at the trap temperatures.

In addition to small quantities of low boiling chlorosilanes such as SlHsClz and SiHCh, the condensate collected in the traps contained about equal parts by weight of unreacted methylene chloride and a high boiling fraction consisting principally of compounds of silicon in which'the silicon atoms were linked by carbon atoms. The

methylene chloride was separated by fractional distillation at atmospheric pressure, leaving a fraction boiling above 155 C. This latter fraction was carefully fractionated at a reduced pressure mm.) to separate compounds identified as being ClaSiCI-IaSiHCh, boiling point of 51.052.5 C. at 10 mm.

=ChSiCH2SiCls. boiling 'point of 63.7-65.0 c.

. atlo mm. (184-5" C. at 156 mm.) [C12 SlCH:]a, melting pt. 81.0-82.5 C.

Another liquid fraction was distilled over between 120' and 187? C. at 10 mm. pressure and was found to contain about 65.1 per cent chlorine. The residue boiling above 200 C. at 10 mm. pressure was a viscous, greenish-black liquid which contained 61.5 per cent chlorine and had the appearance of a high molecular weight, polymeric substance. This compound may be represented by the formula [-SiClzCH-.-] where x is greater than 3. Such polydichlorosilylmethylene compounds would theoretically contain 62.8 per cent chlorine.

The polymeric bodies having the formula [ClzSiCI-Izh specifically the compound [ClzSiCHz]:

which is believed to be a cyclic or closed chain compound, are more fully described and specifically claimed in our copending application Serial No. 433,330, filed concurrently herewith.

Example 11 Using the same apparatus and procedure as in Example I, a mixture of nitrogen and ethylene dichloride in the proportions of 300 c. c. nitrogen and 0.5 gm. ethylene dichloride per minute was passed over a silicon-copper contact mass containing 90 per cent silicon and 10 per cent copper. At a temperature of 370380 C, approximately '70 per cent of the ethylene chloride either reacted with the silicon to form recoverable 'organosilicon compounds or could be recovered as such and recirculated through the reaction tube.

'In addition to low'boiling silicon compounds such as SiHzCla, SiHCl: and sick, the condensate collected in the traps cooled by an ice-water mixture contained-a good yield of 1,2-bis(trichlorosilyl) ethane having a boiling point of 92.5-93 C. at 24-25 mm. pressure and a melting point of 27-29 C. This compound which was liquid at aseaooo temperatures slightly above room temperature crystallized in the form of long prismatic needles when the liquid material was cooled in a refrigerator.

Likewise, organosilicon compounds containing a greater number of methylene groups between the silicon atoms may be prepared by the above-- resins similar to those described, for example, in-- Patents 2,258,218 and 2,258,220 issued t0 Eugene G. Rochow. The halogen and hydrogen attached to the silicon are readily reactable. High boiling oils or plasticizers may be formed by reacting the active halogen atoms with alcohols or with Grignard reagents.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. An organo'silicon compound having the formula xasiwl-h) nSlXiY wherex represents a halogen atom, Y represents an atom selected from the group consisting of hydrogen and a halogen atom of the same type as that represented by X and n is an integer and is at least 1 and not more than 4.

2. An organosiilcon compound having the formula IQSKCHa) nSiXzY where X represents a chlorine atom, Y represents an atom selected, from the group consisting of hydrogen and chlorine, and n is an integer and is at least 1 and not more than 2.

3. 'Irichlorosi]yldichlorosilylmethane.

4. Bis(trichlorosilyl)methane.

5. 1,2-bis(triohlorosilyl)ethane.

6. The method which comprises effecting reaction between heated silicon and a hologenated hydrocarbon of the formula X(CH:) X, wherein X is a halogen atom and n is an integer and is at least 1 and not more than 4, in the presence of a metallic catalyst for said reaction.

'7. Themethod which comprises effecting reaction between heated silicon and ethylene chloride in the presence of a copper catalyst for said reaction.

8. The method which comprises effecting reaction between heated silicon and a chlorinated compound of the formula Cl(CH)nCl, wherein n is an integer and is at least 1 and not more than 2, in the presence of a copper catalyst for said reaction. said reaction being carried out at a temperature of at least 280 C. in the presence of nitrogen.

' WIN'ION I. PATNODE.

ROBERT W. SCHIESSLER. 

